How Long Is THC Detectable? Calculator & Detection Chart

The short answer: anywhere from a few hours to three months — depending on which test is used and how often you consume. A single joint usually clears a urine screening within 1–3 days; daily consumption can stay detectable for 30 days or more, and a hair test looks back up to ~90 days by design. The calculator below shows your estimated window in two clicks.

THC calculator: how long are you detectable?

Pick the test type and your consumption frequency — the calculator returns the range described in the scientific literature. These are published averages for orientation, not a guarantee: metabolism, body fat and dose shift the windows in both directions.

THC detection times: the chart

Every range at a glance, by consumption frequency and test method:

Consumption	Urine	Blood	Saliva	Hair
One-time	1–3 days	12–24 h	12–24 h	usually not detectable
Occasional (≤2×/week)	3–7 days	1–2 days	1–2 days	up to ~90 days
Regular (3–5×/week)	7–21 days	2–3 days	1–3 days	up to ~90 days
Daily	15–30 days	2–7 days	2–3 days	up to ~90 days
Several times a day	30–90 days	7–14 days	2–4 days	up to ~90 days

How your body breaks THC down

After consumption the liver converts THC first into the still-active 11-OH-THC and then into THC-COOH — an inactive metabolite that most urine tests look for. The key detail: THC is fat-soluble. It stores in body fat and is released back slowly over days to weeks.

That is exactly why frequency dominates the detection window: daily consumers build up a depot their body empties gradually, while a one-off leaves barely any reserve. By the way — in raw flower, THC exists as its acid precursor THCA; how heat turns THCA into THC is covered in our guide.

Urine test: the standard

By far the most common test (workplace screenings) doesn't look for THC itself but for the metabolite THC-COOH. The usual screening cutoff is 50 ng/ml; positives are typically confirmed by GC-MS at a lower cutoff (commonly 15 ng/ml). Because THC-COOH accumulates in fat tissue, urine has the longest windows — studies have documented individual heavy-use cases above 90 days.

Blood test: active THC

Blood measures active THC — most relevant in traffic law. After a joint, blood THC drops steeply within hours; with heavy chronic use, however, active THC can stay measurable for days because fat tissue keeps releasing it.

In Germany, road traffic has had a limit of 3.5 ng/ml THC in blood serum since August 2024 (§ 24a StVG) — with stricter rules for new drivers and in combination with alcohol. Rules differ per country and keep changing (updated: August 2026) — check a current source where you live.

Saliva test: the roadside check

Saliva tests detect recent consumption and are the standard roadside procedure across much of Europe. The window is short — usually 12–24 hours after a one-off, up to about 72 hours with heavy chronic use, occasionally longer.

Hair test: the long memory

THC metabolites are built into growing hair. A standard 3–4 cm segment reflects roughly the last 90 days (hair grows ~1 cm per month). A single use often stays below the detection threshold; regular consumption shows up reliably. Washing, dyeing or a short haircut changes little.

What actually influences the breakdown

• Frequency — by far the biggest factor (the fat-tissue depot effect).
• Body fat percentage — more fat tissue means more storage and slower release.
• Dose and potency — 2 g of a 30% flower leaves more behind than one weak joint.
• Metabolism — age, genetics and activity level shift the ranges individually.
• Hydration — drinking a lot briefly dilutes urine but does not speed up elimination (and heavily diluted samples get flagged by labs).

Can you speed up THC elimination?

The honest answer: reliably, only with time. Detox drinks and miracle cures dilute the sample at best — they do not pull THC-COOH out of fat tissue. Exercise helps long-term through fat loss, but an intense workout shortly before a test can temporarily raise levels as stored THC is released. If you need to clear a window, plan with the chart above and round up.

How long is a single joint detectable?

Usually 1–3 days in urine, and around 12–24 hours in blood and saliva. In hair, a single use often stays below the detection threshold.

Does CBD show up on a drug test?

Standard drug tests don't look for CBD. Full-spectrum CBD products can however contain THC traces that add up with heavy daily use — when in doubt, choose isolates with a certificate of analysis.

Sources: Huestis, "Human Cannabinoid Pharmacokinetics", Chemistry & Biodiversity 2007 · Musshoff & Madea, "Review of Biologic Matrices as Indicators of Recent or Ongoing Cannabis Use", Therapeutic Drug Monitoring 2006 · SAMHSA urine cutoff guidelines · § 24a StVG (Germany). This article is for orientation only and is not medical or legal advice.